Solution-providing apparatus and method of manufacturing organic light-emitting diode (oled) display using the apparatus

ABSTRACT

A solution-providing apparatus and method of manufacturing organic light-emitting diode (OLED) display using the apparatus are disclosed. In one aspect, the apparatus comprises a storage unit, a spraying unit, a pipe, an emission-inducing unit, and a spectrometer. The storage unit is configured to store the solution that includes a light emissive material. The spraying unit is configured to spray the solution toward the substrate. The pipe interconnects the storage unit and the spraying unit. The emission-inducing unit is configured to excite the light emissive material of the solution that flows through the pipe so as to emit light from the solution. The spectrometer is configured to measure the wavelength and intensity of the light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35U.S.C. §119 of Korean Patent Application No. 10-2014-0016144, filed onFeb. 12, 2014, the entire contents of which are hereby incorporated byreference.

BACKGROUND

1. Field

The described technology generally relates to a solution-providingapparatus and a method of manufacturing an organic light-emitting diode(OLED) display using the apparatus.

2. Description of Related Technology

An OLED display is a type of flat panel display that has recently beenreplacing liquid crystal displays (LCD). Because the OLED display isself-emissive, it does not need a separate backlight unit that generateslight. Thus, the OLED display is typically thinner than the LCD, and theusage of the OLED display is expanding.

In general, the OLED display includes an anode, a cathode, and anorganic emission layer that is formed between the anode and the cathode.During operation, holes are provided to the organic emission layerthrough the anode, and electrons are provided to the organic emissionlayer through the cathode. Thus, the electrons and holes are combined togenerate an exciton, and light is generated from the organic emissionlayer due to energy generated as the exciton is changed from an excitedstate to a ground state.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One inventive aspect is an apparatus that can measure the concentrationof provided solution.

Another aspect is a method of manufacturing an organic light-emittingdiode (OLED) display by using the apparatus for providing the solution.

Another aspect is an apparatus for providing solution onto a substrateinclude a storage unit, a spraying unit, a pipe, an emission-inducingunit, and a spectrometer. The storage unit stores the solution, thespraying unit is connected to the storage unit and provides the solutionto the substrate, and the pipe provides a flow path through which thesolution flows, to connect the storage unit to the spraying unit. Also,the emission-inducing unit provides energy to the solution flowingthrough the pipe to induce the generation of a light from the solution,and the spectrometer measures the wavelength and intensity of the lightgenerated from the solution.

Also, the solution-providing apparatuses can further include a controlunit that analyzes the concentration of the solution based on thewavelength and intensity of the light measured by the spectrometer, andadjusts the amount of the solution sprayed from the spraying unitdepending on an analyzed concentration.

Another aspect is a method of manufacturing an OLED display includeforming a first electrode on each of a plurality of pixel areas, whereinthe plurality of pixel areas are defined on a substrate; providingsolution onto the first electrode; curing the solution to form anorganic emission layer on the first electrode; forming a secondelectrode on the organic emission layer; and measuring the concentrationof the solution. The measuring of the concentration of the solution isas follows. Energy is provided to the solution to generate a light fromthe solution before providing the solution onto the first electrode,measures the wavelength and intensity of the light generated from thesolution.

Another aspect is a solution-providing apparatus for providing solutiononto a substrate, the apparatus comprising a storage unit configured tostore the solution that includes a light emissive material, a sprayingunit configured to spray the solution toward the substrate, a pipeinterconnecting the storage unit and the spraying unit, anemission-inducing unit configured to excite the light emissive materialof the solution that flows through the pipe so as to emit light from thesolution, and a spectrometer configured to measure the wavelength andintensity of the light.

The above apparatus further comprises a controller configured to i)determine the concentration of the solution based on the measuredwavelength and intensity of the light, and ii) adjust the amount of thesprayed solution based on the determined concentration. In the aboveapparatus, the controller is further configured to i) compare theintensity of the light to a predetermined value, and ii) increase theamount of the solution provided from the spraying unit when thedetermined concentration is less than a predetermined concentration.

The above apparatus further comprises a bypass pipe branched off of thepipe and connected to the storage unit and a valve connected to thebypass pipe and configured to control the flow of the solution thatflows through the bypass pipe, wherein the controller is furtherconfigured to open and close the valve so as to control the flow of thesolution flowing through the pipe when the determined concentration isless than the predetermined concentration.

In the above apparatus, the emission-inducing unit is further configuredto apply an electric field to the solution. In the above apparatus, theemission-inducing unit comprises an anode arranged on one side of thepipe and a cathode arranged on the other side of the pipe, wherein thecathode and the anode are configured to generate the electric field.

In the above apparatus, the pipe comprises a light transmitting unitconfigured to transmit the light to the spectrometer. In the aboveapparatus, the emission-inducing unit comprises a light sourceconfigured to emit light to the solution, wherein the emission-inducingunit is further configured to apply an optical energy to the solution.

In the above apparatus, the pipe comprises a light transmitting unitconfigured to transmit the light to the spectrometer.

In the above apparatus, the emitted light is ultraviolet light.

In the above apparatus, the pipe comprises a main pipe connecting thestorage unit to the spraying unit and a sub pipe branched from the mainpipe, wherein the emission-inducing unit is further configured to excitethe light emission material of the solution flowing through the subpipe.

Another aspect is a method of manufacturing an organic light-emittingdiode (OLED) display, the method comprising forming a first electrode ineach of a plurality of pixel areas, wherein the pixel areas are definedon a substrate, depositing a solution that includes a light emissivematerial onto the first electrode, exciting the light emissive materialof the solution so as to emit light from the solution before depositingthe solution onto the first electrode, measuring the wavelength andintensity of the emitted light, curing the solution so as to form anorganic emission layer over the first electrode, and forming a secondelectrode over the organic emission layer.

The above method further comprises determining the concentration of thesolution and controlling the amount of the solution provided onto thefirst electrode based on the determined concentration.

The above method further comprises comparing the intensity of the lightto a preset value and increasing the amount of the solution when thedetermined concentration is lower than a predetermined concentration.

In the above method, the excitation includes irradiation of light thatcauses the light to be emitted from the solution.

In the above method, the irradiated light is ultraviolet light.

The above method further comprises transmitting the irradiated light andthe emitted light to a spectrometer configured to perform the measuring.

In the above method, the exciting comprises applying an electricalenergy to the solution. In the above method, the electrical energy isgenerated by electrodes that are arranged on a pipe through which thesolution flows. The above method further comprises transmitting theemitted light to a spectrometer that performs the measuring.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a solution-providing apparatusaccording to an embodiment.

FIG. 2 is an enlarged view of a portion of a pipe coupled to anemission-inducing unit shown in FIG. 1.

FIGS. 3A to 3C are graphs that represent the wavelengths and intensitiesof lights measured by a spectrometer shown in FIG. 1.

FIG. 4 is a schematic diagram of a solution-providing apparatusaccording to another embodiment.

FIG. 5 is an enlarged view of a portion of a pipe coupled to anemission-inducing unit shown in FIG. 4.

FIG. 6 is a schematic diagram of a solution-providing apparatusaccording to another embodiment.

FIGS. 7A to 7E represent a method of manufacturing an organiclight-emitting diode (OLED) display by using the apparatus for providingthe solution shown in FIG. 1.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Embodiments of the described technology are described below in detailwith reference to the accompanying drawings. The above objectives,characteristics and effects of the described technology will be easilyunderstood through the following embodiments to be described withreference to the accompanying drawings. However, the describedtechnology is not limited to embodiments to be described below but canbe implemented through various applications and variations. Rather, theembodiments of the described technology to be described below areprovided to make the technical spirit disclosed herein clearer and fullyconvey the scope of the described technology to a person skilled in theart. Thus, the scope of the described technology should not be construedas being limited by embodiments to be described below. The samereference numerals denoted in the following embodiments and theaccompanying drawings represent the same components.

Also, the terms a “first”, a “second”, etc. used herein are not used aslimited meanings but used for the purpose of distinguishing onecomponent from another component. When a portion of a layer, an area, ora component is referred to as being “on” another portion, it can bedirectly on the other portion or intervening layers, areas, orcomponents can also be present. In this disclosure, the term“substantially” includes the meanings of completely, almost completelyor to any significant degree under some applications and in accordancewith those skilled in the art. Moreover, “formed on” can also mean“formed over.”

FIG. 1 is a schematic diagram of a solution-providing apparatusaccording to an embodiment of the described technology. FIG. 2 is anenlarged view of a portion of a pipe coupled to an emission-inducingunit shown in FIG. 1.

Referring to FIGS. 1 and 2, a solution-providing apparatus 500 in thepresent embodiment can be used for manufacturing an organiclight-emitting diode (OLED) display 1000 (of FIG. 7E). Thesolution-providing device 500 can provide solution SL to a substrate SBand can thus be used for forming the organic emission layers EML1 toEML3 (of FIG. 7E) of the OLED display.

The solution-providing apparatus 500 includes a storage unit 10, anemission-inducing unit 100, a spectrometer 200, a spraying unit 400, apipe PB, a first valve V1 and a control unit or controller 300.

The storage unit can receive and store the solution SL. In someembodiments, the solution SL can be provided onto the substrate SB andthen cured so that the organic emission layers can be formed. Thesolution SL can include solvent SV and an emissive material LP. Theemissive material LP can include a fluorescent material or a phosphorousmaterial and the solvent SV can have an electrolytic characteristic sothat an electric field EF can be applied to the solution SL.

The spraying unit 400 is connected to the storage unit 10 via the pipePB, and the spraying unit 400 provides the solution SL onto thesubstrate SB. The spraying unit 400 can be a nozzle that sprays thesolution SL by using an inkjet technique.

The pipe PB provides a flow path FP through which the solution SL flows.The pipe PB connects the storage unit to the spraying unit 400. The pipePB includes a main pipe MP and a sub pipe SP. The main pipe MP connectsthe storage unit 10 to the spraying unit 400. The sub pipe SP branchesout of the main pipe MP and extends to the emission-inducing unit 100.

The first valve V1 is coupled to the sub pipe SP and can control theflow of the solution SL that flows through the sub pipe SP. For example,when the first valve V1 is closed, the flow of the solution SL can beblocked by the first valve V1. Also, when the first valve V1 is open,the solution SL stored in the storage unit 10 can be provided toward theemission-inducing unit 100 through the main pipe MP and the sub pipe SP.

The emission-inducing unit 100 is arranged to be adjacent to the subpipe SP, and the emission-inducing unit 100 applies an electric field EFto the solution SL flowing through the sub pipe SP to induce thegeneration of a light L1 from the solution SL. The emission-inducingunit 100 can apply an electric field to the solution SL to induce thegeneration of the light L1 from the solution SL. The emission-inducingunit 100 can include an anode AE and a cathode CE.

The anode AE is arranged on one side of the sub pipe SP, and the cathodeCE is arranged on the other side of the sub pipe so as to generate anelectric field EF. The electric field EF is applied to the solution SL.In some embodiments, the anode AE and the cathode CE can be arranged toface each other in the sub pipe SP. The principle of inducing thegeneration of the light L1 by the emission stimulating unit 100 is asfollows.

An electrical signal or voltage is applied to the anode AE through afirst wire W1 electrically connected to the anode AE and an electricalsignal or voltage is applied to the cathode CE through a second wire W2electrically connected to the cathode CE. The electric field EF can begenerated by the potential difference between the anode AE and thecathode CE. In this case, a hole is provided to the emissive material LPthrough the solvent SV, and an electron is provided to the emissivematerial LP through the cathode CE and the solvent SV. Thus, theelectron and the hole provided to the organic emission layer arecombined to generate an exciton, and light is generated from theemissive material LP by energy generated as the exciton is changed froman excited state to a ground state.

In some embodiments, the sub pipe SP can include a light shielding unitP1 and a light transmitting unit P2. The light shielding unit P1 can beformed of a plastic material such as poly vinyl chloride (PVC) and thelight transmitting unit P2 can be formed of a material such as quartz soas to transmit the light L1. Thus, the light L1 generated from theemissive material LP can pass through the light transmitting unit P2 andbe emitted to the outside of the sub pipe SP.

The spectrometer 200 can receive the light L1 and can measure thewavelength and intensity of the light L1. The spectrometer 200 can splitthe light L1 into optical components depending on its wavelength and canmeasure the intensity of the optical components obtained through thesplitting. Related descriptions are provided in more detail withreference to FIGS. 3A to 3C.

The control unit 300 can receive information on the wavelength andintensity of the light L1 through a first signal line SL1 and thecontrol unit 300 can analyze or determine the concentration of thesolution SL based on the information. Also, the control unit 300 canprovide a control signal to the spraying unit 400 through a secondsignal line SL2 based on an analyzed concentration. The amount of thesolution SL sprayed from the spraying unit 400 can be adjusted by thecontrol signal.

For example, when the analyzed concentration is lower than a presetconcentration, the control unit 300 can transmit a control signal to thespraying unit 400 through the second signal line SL2 so as to increasethe amount of the solution SL sprayed from the spraying unit 400. Also,when the analyzed concentration is higher than a preset concentration,the control unit 300 can transmit a control signal to the spraying unit400 through the second signal line SL2 so as to decrease the amount ofthe solution SL sprayed from the spraying unit 400.

A method of analyzing the concentration of the solution SL by thecontrol unit 300 in linkage with the spectrometer is as follows.

FIGS. 3A to 3C are graphs that represent the wavelengths and intensitiesof light measured by a spectrometer shown in FIG. 1.

Referring to FIGS. 1, 2 and 3A, wavelength vs. intensity of the light L1split into a plurality of optical components by the spectrometer 200 isshown. More specifically, the x-axis of the graph shown in FIG. 3Arepresents the wavelength of the light L1 in units of nanometers (nm),and the y-axis of the graph represents the intensity of the light L1with relative values.

Referring to a first peak PK1 represented in the graph, the wavelengthof the first peak PK1 is about 400 nm to about 480 nm that correspondsto the wavelength of a blue light, and the intensity of the first peakPK1 is represented by a first intensity I1.

When the amount of the solution SL flowing through the flow path FP ofthe sub pipe SP per unit time is controlled to be constant, thefrequency and efficiency of the light L1 increase as the amount of theemissive material LP in the solution SL increases. Therefore, the firstintensity I1 can increase. Thus, the relative value of a firstconcentration of the amount of the emissive material LP contained in thesolution SL can be defined based on the first intensity I1 of the firstpeak PK1.

Also, the proper concentration obtained by quantitatively analyzing thesolution SL by using another method can be predetermined. Referring toFIGS. 3A to 3C, it is assumed that the control unit 300 sets the firstconcentration to the proper concentration.

Referring to a second peak PK2 shown in FIG. 3B, the wavelength of thesecond peak PK2 is about 400 nm to about 480 nm that corresponds to thewavelength of a blue light. The intensity of the second peak PK2 isrepresented by a second intensity I2 that is less than the firstintensity I1. When defining a second concentration of the solution SLbased on the second intensity I2, the control unit 300 can determinethat the second concentration is less than the proper concentration.

Referring to a third peak PK3 of the graph shown in FIG. 3C, thewavelength of the third peak PK3 is about 400 nm to about 480 nm thatcorresponds to the wavelength of a blue light. However, the intensity ofthe third peak PK3 is represented by a third intensity I3 that isgreater than the first intensity I1. When defining a third concentrationof the solution SL based on the third intensity I3 of the third peakPK3, the control unit 300 can determine that the third concentration isgreater than the proper concentration.

The solution SL includes the solvent SV and the emissive material LP.After the solution SL is sprayed, the solvent SV can be removed by athermal treatment process. For example, when attempting to form anylayer on the substrate SB by using the solution SL, the solution SL isfirst sprayed onto the substrate SB by using the spraying unit 400 andthen the sprayed solution SL can be thermally treated to remove thesolvent SV from the solution SL. As a result, the emissive material LPcan remain on the substrate SB so as to form the layer on the substrateSB and little solvent SV remains on the layer.

Thus, when the concentration of the solution SL is analyzed by thespectrometer 200 and the control unit 300 as described with reference toFIGS. 3A to 3C, there is no need to correct the amount of the solutionSL provided to the substrate SB based on the concentration. For example,when the concentration of the solution SL is less than the presetconcentration, the control unit 300 can transmit a control signal to thespraying unit 400 so as to increase the amount of the solution SLsprayed from the spraying unit 400. Thus, when the concentration of thesolution SL, the amount of the solution SL provided to the substrate SBand the amount of the emissive material LP contained in the solution SLincrease, it is possible to prevent the thickness of a layer fromdecreasing.

As another example, when the concentration of the solution SL is greaterthan the preset concentration, the control unit 300 can transmit acontrol signal to the spraying unit 400 so as to decrease the amount ofthe solution SL sprayed from the spraying unit 400. Thus, when theconcentration of the solution SL is high and when the amount of thesolution SL provided to the substrate SB and the amount of the emissivematerial LP contained in the solution SL decrease, it is possible toprevent the thickness of a layer from increasing.

FIG. 4 is a schematic diagram of a solution-providing apparatusaccording to another embodiment of the described technology. FIG. 5 isan enlarged view of a portion of a pipe coupled to the emission-inducingunit shown in FIG. 4. In describing FIGS. 4 and 5, the componentsdescribed above are denoted by the reference numerals and their detaileddescriptions are left out.

Referring to FIGS. 4 and 5, a solution-providing apparatus 501 includesan emission-inducing unit 50. But unlike the embodiment shown in FIG. 1,the emission-inducing unit 50 provides optical energy to the solution SLthat flows through the sub pipe SP. In some embodiments, theemission-inducing unit 50 can be a light source that radiates a radiantlight L2, and the emission-inducing unit 50 provides the radiant lightL2 to the solution SL and absorbs energy from the radiant light L2 togenerate the light L1. In some embodiments, the wavelength of theradiant light L2 can be less than the wavelength of a visible light. Theradiant light L2 can be ultraviolet radiation.

Like the embodiment previously described with reference to FIGS. 1 and2, the spectrometer 200 receives the light L1 and measures thewavelength and intensity of the light L1. Also, the control unit 300receives information on the wavelength and intensity of the light L1measured by the spectrometer 200 through the first signal line SL1. Thecontrol unit 300 analyzes the concentration of the solution SL based onthe information. Also, the control unit 300 can provide a control signalto the spraying unit 400 through the second signal line SL2 based on ananalyzed concentration. The amount of the solution sprayed from thespraying unit 400 can be adjusted by the control signal.

FIG. 6 is a schematic diagram of a solution-providing apparatusaccording to another embodiment of the described technology. Indescribing FIG. 6, the components described above are denoted by thereference numerals and their detailed descriptions are left out.

Referring to FIG. 6, a solution-providing apparatus 502 includes thestorage unit 10, an emission-inducing unit 100, the spectrometer 200,the control unit 300, the spraying unit 400, a main pipe MP, a bypasspipe BP, first to third valves V1 to V3, a third signal line SL3, and afourth signal line SL4.

The bypass pipe BP is branched out of the main pipe MP and connected tothe storage unit 10. The second valve V2 is connected to the bypass pipeBP and can control the flow of the solution SL that flows through thebypass pipe BP. Also, the third valve V3 is connected to the main pipeBP and can control the flow of the solution SL that flows through themain pipe MP.

For the solution-providing apparatus 502 having a configurationdescribed above, when the first valve V1 opens, the solution SL isprovided to the emission-inducing unit 100, and the concentration of thesolution SL is analyzed by the control unit 300 after the light has beenreceived by the spectrometer 200. As previously described with referenceto FIGS. 3A to 3C, when the concentration of the solution SL is not theproper concentration, the control unit 300 can transmit a control signalto the third valve V3 through the third signal line SL3 to close thethird valve V3. As a result, the flow of the solution SL provided to thespraying unit 400 can be blocked.

Also, the control unit 300 can transmit the control signal to the secondvalve V2 through the fourth signal line SL4 to open the second valve V2.Thus, the solution SL flowing through the main pipe MP is collected inthe storage unit through the bypass pipe BP. As previously described, itis possible to perform an operation to correct the concentration of thesolution SL stored in the storage unit 10 when the solution SL does nothave the proper concentration collected in the storage unit 10. Thus, itis possible to prevent the solution SL that does not have the properconcentration from becoming provided to the spraying unit 400.

FIGS. 7A to 7E represent a method of manufacturing an organiclight-emitting diode (OLED) display by using the apparatus for providingthe solution shown in FIG. 1. In describing FIGS. 7A to 7E, thecomponents described above are denoted by the reference numerals andtheir detailed descriptions are left out.

Referring to FIG. 7A, first to third pixel areas PA1 to PA3 are definedon the substrate SB. A gate insulating layer L10, an interlayerinsulating layer L20, and a planarization layer L30 are formed on thesubstrate SB. First to third pixels PXL1 to PXL3 (of FIG. 7E) are formedon the first to third pixel areas PA1 to PA3. Although not shown in FIG.7A, a driving transistor is formed on each of the first to third pixelareas PA1 to PA3 before forming the planarization layer L30 so that itis possible to switch the driving of the first to third pixels PXL1 toPXL3 (of FIG. 7E).

After the planarization layer L30 is formed, a first electrode E1 isformed on each of the first to third pixel areas PA1 to PA3, and a pixeldefining layer PDL is formed. Openings OP can be formed on the pixeldefinition layer PDL to face the first to third pixel areas PA1 to PA3,respectively.

Referring to FIG. 7B, first to third extra emission layers AL1 to AL3are respectively formed on the first to third pixel areas PA1 to PA3. Amethod of forming the first to third extra emission layers AL1 to AL3 isas follows.

The solution SL is provided onto the first electrode E1 arranged on thefirst pixel area PA1 by using the spraying unit 400. As a result, thefirst extra emission layer AL1 having a first thickness T1 is formed.Also, other solutions SL-1 and SL-2 are provided to the second and thirdpixel areas PA2 and PA3 by using other spraying units 401 and 402 thatare one-to-one connected to other pipes MP-1 and MP-2. As a result, thesecond and third extra emission layer AL2 and AL3 are respectivelyformed on the second and third pixel areas PA2 and PA3.

In some embodiments, the first to third pixels PXL1 to PXL3 (of FIG. 7E)that emit lights of different colors can be formed on the first to thirdpixel areas PA1 to PA3. In this case, the first extra emission layer AL1can include, e.g., a red emissive material and solvent, the second extraemission layer AL2 can include, e.g., a green emissive material andsolvent, and the third extra emission layer AL3 can include, e.g., ablue emissive material and solvent.

Referring to FIGS. 1 and 7C, when the concentration of the solution SLis less than the proper concentration, the control unit 300 can transmita control signal to the spraying unit 400 so that the spraying unit 400can further provide the solution SL to the first pixel area PAL As aresult, the solution SL can be provided to the first extra emissionlayer AL1 (of FIG. 7B) so as to form a fourth extra emission layer AL4.A second thickness T2 of the fourth extra emission layer AL4 is greaterthan the first thickness T1 of the first extra emission layer AL1.

Referring to FIG. 7D, the first to third emission layers EML1 to EML3are formed by performing a thermal treatment process in which heat HT isapplied to the second to fourth extra emission layers AL2 to AL4 (ofFIG. 7C). Because each of the second to fourth extra emission layers hasa liquid state in which solvent and an emissive material are included,the solvent is removed by the thermal treatment process. The emissivematerial that is a solid component remains on each of the first to thirdpixel areas PA1 to PA3, and as a result, the first to third emissionlayers EML1 to EML3 are formed.

When the predetermined thickness of the first emission layer EML1 is athird thickness T3, the solvent contained in the fourth extra emissionlayer AL4 (of FIG. 7C) is removed when performing the thermal treatmentprocess and thus the third thickness T3 is less than the secondthickness T2 (of FIG. 7C). Also, when the process shown in FIG. 7C isleft out unlike the embodiment of the described technology, the firstemission layer EML1 can have a thickness that is less than the thirdthickness T3. However, in the embodiment of the described technology,when the concentration of the solution (of FIG. 7C) is lower than theproper concentration, it is possible to prevent the first emission layerEML1 from having a thickness less than the third thickness T3 byincreasing the amount of the solution provided to the first pixel areaPA1, as seen in the process shown in FIG. 7C.

Referring to FIG. 7E, a second electrode E2 is formed on the first tothird organic emission layers EML1 to EML3. As a result, the first tothird pixels PXL1 to PXL3 that respectively correspond one-to-one to thefirst to third pixel areas PA1 to PA3 are formed. In another embodiment,a hole injection layer, a hole transport layer, an electron transportlayer, and an electron injection layer can be further formed on each ofthe first to third pixels PXL1 to PXL3.

Then, a sealing layer 150 that substantially covers the first to thirdpixels PXL1 to PXL3 is formed and the manufacturing of the OLED display1000 is completed.

According to embodiments of the described technology, before solution isprovided to the substrate through the spraying unit of thesolution-providing apparatus, it is possible to analyze theconcentration of the solution and it is possible to correct the amountof the solution provided to the substrate based on analysis. Thus, whenthe solution is cured to form a layer, it is possible to prevent thethickness of the layer from becoming non-uniform due to a difference inconcentration of the solution.

Also, when the solution-providing apparatus is used for manufacturingthe emission layer of the OLED display, it can be easy to uniformlymanufacture the thickness of the emission layer. Thus, the amount of alight generated from the emission layer can become uniform.

While the inventive technology has been described above, a personskilled in the art can understand that many modifications and variationscan be made without departing from the spirit and scope of the presentinvention defined in the following claims. Thus, the technical scope ofthe present invention is not limited to those described in the detaileddescription but should be defined by the following claims.

What is claimed is:
 1. A solution-providing apparatus for providingsolution onto a substrate, the apparatus comprising: a storage unitconfigured to store the solution that includes a light emissivematerial; a spraying unit configured to spray the solution toward thesubstrate; a pipe interconnecting the storage unit and the sprayingunit; an emission-inducing unit configured to excite the light emissivematerial of the solution that flows through the pipe so as to emit lightfrom the solution; and a spectrometer configured to measure thewavelength and intensity of the light.
 2. The solution-providingapparatus of claim 1, further comprising a controller configured to i)determine the concentration of the solution based on the measuredwavelength and intensity of the light, and ii) adjust the amount of thesprayed solution based on the determined concentration.
 3. Thesolution-providing apparatus of claim 2, wherein the controller isfurther configured to i) compare the intensity of the light to apredetermined value, and ii) increase the amount of the solutionprovided from the spraying unit when the determined concentration isless than a predetermined concentration.
 4. The solution-providingapparatus of claim 2, further comprising: a bypass pipe branched off ofthe pipe and connected to the storage unit; and a valve connected to thebypass pipe and configured to control the flow of the solution thatflows through the bypass pipe, wherein the controller is furtherconfigured to open and close the valve so as to control the flow of thesolution flowing through the pipe when the determined concentration isless than the predetermined concentration.
 5. The solution-providingapparatus of claim 1, wherein the emission-inducing unit is furtherconfigured to apply an electric field to the solution.
 6. Thesolution-providing apparatus of claim 5, wherein the emission-inducingunit comprises: an anode arranged on one side of the pipe; and a cathodearranged on the other side of the pipe, wherein the cathode and theanode are configured to generate the electric field.
 7. Thesolution-providing apparatus of claim 5, wherein the pipe comprises alight transmitting unit configured to transmit the light to thespectrometer.
 8. The solution-providing apparatus of claim 1, whereinthe emission-inducing unit comprises a light source configured to emitlight to the solution, wherein the emission-inducing unit is furtherconfigured to apply an optical energy to the solution.
 9. Thesolution-providing apparatus of claim 8, wherein the pipe comprises alight transmitting unit configured to transmit the light to thespectrometer.
 10. The solution-providing apparatus of claim 8, whereinthe emitted light is ultraviolet light.
 11. The solution-providingapparatus of claim 1, wherein the pipe comprises: a main pipe connectingthe storage unit to the spraying unit; and a sub pipe branched from themain pipe, wherein the emission-inducing unit is further configured toexcite the light emission material of the solution flowing through thesub pipe.
 12. A method of manufacturing an organic light-emitting diode(OLED) display, the method comprising: forming a first electrode in eachof a plurality of pixel areas, wherein the pixel areas are defined on asubstrate; depositing a solution that includes a light emissive materialonto the first electrode; exciting the light emissive material of thesolution so as to emit light from the solution before depositing thesolution onto the first electrode; measuring the wavelength andintensity of the emitted light; curing the solution so as to form anorganic emission layer over the first electrode; and forming a secondelectrode over the organic emission layer.
 13. The method of claim 12,further comprising: determining the concentration of the solution; andcontrolling the amount of the solution provided onto the first electrodebased on the determined concentration.
 14. The method of claim 13,further comprising: comparing the intensity of the light to a presetvalue; and increasing the amount of the solution when the determinedconcentration is lower than a predetermined concentration.
 15. Themethod of claim 12, wherein the excitation includes irradiation of lightthat causes the light to be emitted from the solution.
 16. The method ofclaim 15, wherein the irradiated light is ultraviolet light.
 17. Themethod of claim 15, further comprising transmitting the irradiated lightand the emitted light to a spectrometer configured to perform themeasuring.
 18. The method of claim 12, wherein the exciting comprisesapplying an electrical energy to the solution.
 19. The method of claim18, wherein the electrical energy is generated by electrodes that arearranged on a pipe through which the solution flows.
 20. The method ofclaim 19, further comprising transmitting the emitted light to aspectrometer that performs the measuring.